In recent years, with progress in miniaturization and lower power consumption of semiconductor devices, these semiconductor devices have started to show some limitations. Studies are being carried out on organic material devices as a functional element with higher density and lower power consumption. For example, by forming a self-assembled monolayer (SAM) between metal portions facing each other via a so-called nano-gap, a gap of 5 nm or smaller, it is possible to exploit the SAM-intrinsic electroconductivity characteristics. However, it is not an easy task to form the SAM uniformly in the fine nano-gap.